For example, in JP-A-2001-80774, there is disclosed a sheet supply device including: a pick-up roller (delivery roller) which is provided to be movable up and down so as to be brought into contact with sheets stacked on a stacking portion, and a separation mechanism having a paper feed roller (separation roller) and a separation pad (separation unit), which is provided in the more downstream side of the conveying direction than the pick-up roller. The pick-up roller is rotated in a state of being brought into contact with the sheet on the stacking portion, so that the sheet is delivered to the separation mechanism. Further, the sheets are separated one by one by the nip of the separation pad and the separation roller to be delivered to the more downstream side of the conveying direction.
Here, when the pick-up roller always is brought into contact with the sheet, there is a problem in that paper powder or conveying sound are produced or the conveying burden is increased by the friction between the pick-up roller and the sheet. Subsequently, in the sheet supply device of JP-A-2001-80774, when the sheet reaches the nip position between the paper feed roller and the separation roller, a solenoid switch is turned on to separate the pick-up roller from the sheet on the stacking portion.